Sinonasal Metastasis of a Pancreatic Mucinous Adenocarcinoma: An Unusual Case Report.

Metastases to the sinonasal tract are exceedingly rare and often signify advanced-stage disease. Among known primary sites, pancreatic adenocarcinoma is an exceptional origin for sinonasal dissemination. We report the case of a 66-year-old male previously diagnosed with mucinous pancreatic adenocarcinoma, who presented with persistent right-sided nasal obstruction. Imaging revealed an aggressive ethmoidal mass extending into the orbit, nasal cavity, and anterior cranial fossa. Histopathological analysis following biopsy proved it was consistent with pancreatic origin. Given the patient's known cancer history and the radiological and immunophenotypic findings, a diagnosis of sinonasal metastasis from pancreatic adenocarcinoma was confirmed. This case underscores the diagnostic challenges presented by sinonasal masses in cancer patients, especially when symptoms are nonspecific. It highlights the rarity of sinonasal metastases from pancreatic cancer and the importance of including metastatic disease in the differential diagnosis of sinus masses, especially in oncologic patients.